The present invention relates to techniques for actively configuring programmable circuits, and more particularly, to techniques for actively configuring programmable circuits using an external memory and determining whether the external memory device is supported by a programmable integrated circuit.
Programmable integrated circuits are configured (i.e., programmed) using configuration data. Configuration data used to configure a programmable circuit can be stored in an external configuration device.
The external memory device controls the transfer of the configuration data to the programmable circuit. The configuration device has to send the data in a format that the programmable circuit can accept. The task of the programmable circuit is merely to accept the data. The programmable circuit does not contain data that identifies the configuration device. Thus, the configuration device is the master, and the programmable circuit is the slave.
However, the costs associated with a configuration device are typically high, because the configuration device must be programmable to implement the configuration data transfer functions. Therefore, it would be desirable to provide a system for transferring configuration data to a programmable circuit that reduces the cost and complexity of prior art configuration devices. Also, it would be desirable to provide a system to enable a programmable circuit to identify external configuration devices and to support only particular configuration devices, if desired.